/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hcatalog.cli.SemanticAnalysis;

import java.io.Serializable;
import java.util.List;

import org.apache.hadoop.hive.metastore.api.Database;
import org.apache.hadoop.hive.ql.exec.Task;
import org.apache.hadoop.hive.ql.metadata.Hive;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.parse.ASTNode;
import org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer;
import org.apache.hadoop.hive.ql.parse.HiveParser;
import org.apache.hadoop.hive.ql.parse.HiveSemanticAnalyzerHookContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.plan.CreateDatabaseDesc;
import org.apache.hadoop.hive.ql.plan.DDLWork;
import org.apache.hadoop.hive.ql.security.authorization.Privilege;
import org.apache.hcatalog.common.HCatConstants;

final class CreateDatabaseHook extends HCatSemanticAnalyzerBase {

    String databaseName;

    @Override
    public ASTNode preAnalyze(HiveSemanticAnalyzerHookContext context, ASTNode ast)
        throws SemanticException {

        Hive db;
        try {
            db = context.getHive();
        } catch (HiveException e) {
            throw new SemanticException("Couldn't get Hive DB instance in semantic analysis phase.", e);
        }

        // Analyze and create tbl properties object
        int numCh = ast.getChildCount();

        databaseName = BaseSemanticAnalyzer.getUnescapedName((ASTNode) ast.getChild(0));

        for (int num = 1; num < numCh; num++) {
            ASTNode child = (ASTNode) ast.getChild(num);

            switch (child.getToken().getType()) {

            case HiveParser.TOK_IFNOTEXISTS:
                try {
                    List<String> dbs = db.getDatabasesByPattern(databaseName);
                    if (dbs != null && dbs.size() > 0) { // db exists
                        return ast;
                    }
                } catch (HiveException e) {
                    throw new SemanticException(e);
                }
                break;
            }
        }

        return ast;
    }

    @Override
    public void postAnalyze(HiveSemanticAnalyzerHookContext context,
                            List<Task<? extends Serializable>> rootTasks) throws SemanticException {
        context.getConf().set(HCatConstants.HCAT_CREATE_DB_NAME, databaseName);
        super.postAnalyze(context, rootTasks);
    }

    @Override
    protected void authorizeDDLWork(HiveSemanticAnalyzerHookContext context,
                                    Hive hive, DDLWork work) throws HiveException {
        CreateDatabaseDesc createDb = work.getCreateDatabaseDesc();
        if (createDb != null) {
            Database db = new Database(createDb.getName(), createDb.getComment(),
                createDb.getLocationUri(), createDb.getDatabaseProperties());
            authorize(db, Privilege.CREATE);
        }
    }
}